Concrete mixing apparatus



Feb. 13, 1962 G, MAXON, JR 3,021,122

CONCRETE MIXING APPARATUS Filed Nov. 7, 1960 5 Sheets-Sheet 1 CONCRETE MIXING APPARATUS Filed NOV. 7, 1960 5 Sheets-Sheet 2 /@zz my Mmm Jh mi Feb. 13, 1962 Filed Nov. 7. 1960 G. MAXON, JR

CONCRETE MIXING APPARATUS 5 Sheets-Sheet 3 Feb. 13, 1962 G. MAxoN, JR 3,021,122

CONCRETE MIXING APPARATUS Filed Nov. 7, 19Go 5 sheets-sheet 4 67m Way Mraz: Jr.

Feb. 13, 1962 G. MAXON, JR 3,021,122

CONCRETE MIXING APPARATUS Filed Nov. 7, 1960 5 Sheets-Sheet 5 3,021,122 CONCRETE MIXlNG APPARATUS Glenway Maxon, lr., 171%4 N. Farwell Ave., Milwaukee, Wis. Filed Nov. 7, 1960, Ser. No. 67,586 6 Claims. (Cl. 259-171) This invention relates to improvements in concrete mixing apparatus on the order of that disclosed in my Patent No. 2,590,438, issued March 25, 1952, wherein a rotatable mixing drum is supported at an elevation above ground level for tilting motion from a mixing position to a discharging position, at which its contents may be discharged directly into the body of a transit truck.

More particularly, this invention concerns concrete mixing apparatus of the type having a rotatable mixing drum with an opening in its rear through which aggregates may be charged into the interior of the drum, and having a discharge opening at its forward end through which its contents debouche upon tilting of the drum out of a mixing position at which its axis is substantially horizontal, toward a discharging position at which the rear of the drum is elevated and its forward or discharge end is lowermost.

As in my aforesaid Patent No. 2,590,438, it is a general object of this invention to so mount the mixing drum from a supporting structure therefor that the drum is located at a minimum elevation above ground level, but high enough for convenient discharge of its contents directly into the body of a transit truck, and that controlled pouring of the drum contents is achieved when it is tilted out of its mixing position.

While the concrete mixing apparatus of this invention achieves certain advantages which are common to that disclosed in my aforesaid Patent No. 2,590,438, it is also related in other respects to the concrete mixing apparatus disclosed in my later Patent No. 2,801,085, issued July 30, 1957, particularly in that it features means for supporting the mixing drum for tilting discharging motion not about a fixed axis as was usually the case heretofore, but in such a way that the drum is moved bodily for? wardly during the tilting discharge operation. In fact, by this invention, the drum is so mounted that during tilting thereof, its discharge mouth is carried forwardly a substantial distance farther than was possible with the construction disclosed in my aforesaid Patent No. 2,801,085.

This is especially important in concrete mixing plants where the drum is intended to be discharged directly into the body of a transit truck, which heretofore had to be maneuvered extremely close to the supporting columns of the mixing apparauts. lt was not unusual in the past, therefore, that the transit truck was driven against the supporting columns with resulting damage to the truck and also to the mixing plant itself.

In general, therefore, it is another object of this invention to provide concrete mixing apparatus of the type including a mixing drum, mounted on a supporting framework for tilting motion to a discharging position by means which causes the discharge mouth of the drum to be carried a distance farther forwardly during tilting of the drum than was possible heretofore, to obviate the need for careful maneuvering of the transit truck intended to receive the drum contents when it is driven into position alongside of the mixing plant.

Another objective of this invention resides in the provision of concrete mixing apparatus of the character described wherein the drum is so supported and guided for tilting motion out of its mixing position that it is caused to move bodily during initial'discharging motion, mainly in the forward direction, to carry the rear or charging end of the drum away from a charging chute having its extremity normally positioned within the charging openfront end of the drum broken away to show its interior` liza 'a ice ing in the rear of the drum to obviate the need for retracting the charging chute before discharging motion of the drum can be commenced.

Another purpose of this invention resides in the provision of concrete mixing apparatus Vof the character described wherein the tilting motion of the mixing drum, during discharge of its contents, is confined to a predetermined path that causes the materials debouching from its mouth to flow into a localized zone of substantially small area, regardless of the tilted position of the drum, to thus enable discharge of concrete into smaller transit truck bodies, or even a small collecting cone, without any tendency for the concrete to spew or spurt forwardly in uncontrolled fashion at any stage of the discharging operation.

In this last respect, it is a purpose of this invention to provide concrete mixing apparatus of the character described with means to control the tilting discharge motion of the mixing drum in suchv a way that the discharge mouth of the drum is moved along the llow path of concrete issuing from the mouth of the drum throughout substantially the entire range of tilting discharge motion of the drum.

While the invention herein presented makes it possible to install the mixing drum and its supporting structure in existing plants intended for hatching transit trucks without altering the height of the plant, it is also possible to position one or more mixing drums along with their supporting structures at a higher elevation on the plant where a battery of such drums may discharge into a common collecting hopper and then into a transit truck or the like.

A more specific object of the invention resides in the provision of concrete mixing apparatus of the character described wherein the mixing drum is supported upon an upright framework by cooperating suspension and guide links which so control and guide the tilting discharging motion of the drum during application of tilting force thereto that the drum initially moves forwardly with but little upward tilt of its rear to efect discharge of the main bulk of materials from greatest lift or upward tilt is imparted to the drum as it nears its fully tilted position, and at a time when much of the concrete has already been discharged therefrom. This, of course, achieves the advantage of requiring less effort to move the drum from its mixing position to its extreme discharging position.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by understood'that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which: n

FIGURE l is a side elevational view of mixing apparatus embodying this invention, portions of the mixing drum thereof being broken away and shown in section, and illustrating by construction lines the tilted discharging position of the drum with respectto a transit truck alongside the apparatus;

FIGURE 2 is a side elevational view similar to PIG. URE 1, but showing the drum tilted to its extreme discharging position;

FIGURE 3 is a front elevational view of the mixing apparatus shown in FIGURE 1, with portions kof the the drum, and wherein the the appended claims, it being' FIGURE 4 is a cross sectional view taken through the apparatus on the plane of the line 4--4 in FIGURE l, and showing the underside of the drum;

FIGURE 5 is an enlarged detail sectional view taken through FIGURE 3 on the plane of the line 5-5g and FIGURE 6 is a diagrammatic side elevational view of the apparatus in which the position ofthe mixing drum is indicated at several different points along its path of tilting discharge motion.

Referring now particularly to the accompanying drawings, the concrete mixing apparatus of this invention has been shown as comprising a mixing drum 5 nested in and rotatably mounted to turn about its axis on a U- shaped tilt frame or cradle 6 in more or less conventional fashion. The cradle, in turn, is carried by a supporting structure or framework, generally designated 7, comprising four upright spaced apart columns arranged at the corners of a rectangle, there being two front columns 8 and two rear columns 9. These columns are joined by high and low level side beams 10 and 11, respectively, and similar high and low level transverse beams 10 and 11', respectively. The upper transverse beam 16' is fixed lengthwise between the two upper side beams 1t), a short distance rearwardly of the front columns 8.

The mixing drum is supported from the framework 7 by means of upper and lower structures 13 and 14, respectively, which denne links that control and guide the forward tilting motion of the drum from the mixing position thereof shown in solid lines in FIGURE 1 to its fully tilted discharging position shown in solid lines in FIG- URE 2, at which the contents of the drum may be discharged directly into the body of a transit truck in position alongside the front columns 8.

The drum may be of more or less conventional construction having a cylindrical medial section 16 carrying a ring gear 17 by which it may be driven from an electric motor 18 on the cradle, through a drive pinion 19 which meshes with the ring gear. The drum also has frustoconical front and rear end sections 21 and 22, respectively, the large diameter end of each being joined to the cylindrical medial section 16. The forward end section 21, however, is longer than the rear section 22, and it terminates in a discharge mouth 23 that is coaxial with the drum. The frusto-conical rear section 22 of the drum is partially closed by a rear wall 24 which is normal to the axis of the drum and contains a charging opening 2S that is coaxial with but slightly larger in diameter than the discharge mouth 23 at the front of the drum.

The cradle 6, which is kof the usual U-shaped coniiguration, provides upright posts 27 which are joined to and project upwardly from a substantially horizontal cross beam 28 that provides the bight of the cradle. T he cradle may be said to embrace the lower one-half of the mixing drum, at the forward portion of its cylindrical medial section 16.

Like the cradle, the upper link structure 13 is also U-shaped, although it is inverted to embrace the upper one-half of the drum. Its bight portion 29 extends horizontally across the supporting framework 7 beneath the transverse beam 10' on the framework to which it is pivotally connected as at 31, to swing back and forth about a horizontal axis intermediate the front and rear columns 8 and 9 somewhat rearwardly of the posts 27 of the cradle. The opposite arms 32 of the link structure 13 extend downwardly from its bight 29 to the upper ends of the cradle posts 27, and their lower ends are pivotally connected to the cradle posts as at 33.

The mixing drum thus may be said to be suspended from the upper link structure 13 for back and forth swinging motion with it and for turning movement relative thereto, about a transverse axis defined by the pivots 33 and which passes through the medial portion of the drum close to its axis.

Normally, that is in the horizontal mixing position of the drum 5, the upper supporting link structure 13 may be said to occupy a substantially pendant position with its arms 32 extending -downwardly at a slight forward inclination from the pivotal connections 31.

The lower structure 14 provides a guide link that extends fore and aft in the space ahead of the rear columns 9. It comprises a fabricated rectangular frame having its rear pivotally connected, as at 34, to a crossbeam 35 joining the rear columns 9 at an elevation such as to be located behind the mixing drum. It extends forwardly from the pivots 34, beneath the drum, to have its front portion pivotally connected as at 36 to the bight 28 of the cradle. v

The pivot axes 31, 33, 34 and 36 are all parallel, and disposed transversely of the framework 7, and hence crosswise of the axis of rotation of the mixing drum 5.

In the normal or mixing position of the drum 5, the

lower link structure 14 extends at a slight downward inclination with respect to horizontal, so that its rear pivots 34 are located a slight distance above the bottom of the cylindrical medial section 16 of the drum. From the description thus far, it will be seen that while the mixing drum is tiltably suspended from the upper link structure 13, the llower link structure 14 serves to control and guide the tilting movement of the mixing drum and to constrain it to a combination of counterclockwise tilting and forward bodily movements to and through the several positions indicated in FIGURE 6, where the solid lines show the mixing position of the drum and the construction lines indicate the forward advance thereof, at five different stages, toward its extreme discharging position.

It is important to no-te that the link pivots are so disposed with respect to the drum that during initial motion of the mixing drum 5 out of its mixing position, the drum will be bodily shifted forwardly to a greater extent than it will be tilted in the counterclockwise direction, and that this condition is reversed during the latter stages of the discharging motion of the drum during which its rear is elevated at a greater rate. This achieves the advantage of enabling the drum to be moved forwardly away from a charging chute 38 having its extremity normally received in the charging opening 25 in the rear of the drum, without the necessity for retracting the chute as was customary heretofore. Consequently, the charging chute, as well as a water supply pipe 39 thereon, may occupy a fixed position on the framework 7 to simplify the plant generally.

For example, referring to FIGURE 6, it will be seen that with but a very small amount of upward swinging motion of the lower link structure 14 about its pivots 34, on the order of about one degree of are, the rear wall 24 of the drum is moved forwardly to the dotted line position 24', while the lower edge 2S of the charging opening in the rear wall of the drum is still no higher than the lower edge of the charging chute 38.

It will also be appreciated that much of the concrete will have been discharged from the drum in the first stages of its discharging motion during which the drum is moved bodily forwardly a substantial distance and tilted only a small amount in the counterclockwise direction. Hence, there is less weight to be lifted during the final stages of discharging motion of the drum.

The desired forward motion of the drum as it is initially moved out of its mixing position results largely from the fact that the lower end of the suspension link 13 swings forwardly with but very slight upward motion from the position of the pivots 33 shown in FIGURE 1, to the position of the same pivots 33 in the l{irst tilted position of the drum indicated in FIGURE 6. At the same time, during this motion of the upper `link structure, the forward end of the guide link 14 also travels forwardly due to the factthat it is approaching a horizontal position. The combined motions of the links during this initial movement of the drum out of its mixing position, however, also effects a degree of counterclockwise tilting of the drum about the pivots 33 at the lower end of the suspension link 13.

The upper link 13 is so pivotally suspended from the framework 7 that its pivots 33 continue to travel both upwardly and forwardly during the entire period of tilting discharging motion of the drum. The pivots 36 at the forward end of the guide link 14, however, travel upwardly and forwardly only until the lower link reaches a horizontal position, after which time the pivots 36 travel upwardly and slightly rearwardly, so that during the final stages of tilting discharge of the drum, the rear of the drum is lifted much more rapidly than during the first stages of discharge motion of the drum.

This tilting and concurrent forward bodily shifting of the mixing drum during discharge of its contents is also important for the reason that it causes the discharge mouth of the drum to be carried a substantial distance forwardly of its normal location, enabling its contents to debouche into the body of a transit truck 15 spaced farther from the front of the framework 7 than would otherwise be possible. In addition, the pivots of the links 13 and 14 are so located as to cause the discharge mouth 23 of the drum to travel substantially along the tiow path of concrete discharging from the drum, during the entire tilting discharging motion of the drum. Hence, the drum can discharge into a very localized area, for example, into smaller truck bodies or even small diameter collecting cones or hoppers, or even small buckets.

According to this invention, the mixing drum is moved out of its mixing position and carried to any or all of its discharging positions by means of a pair of single-acting hydraulic operators generally designated 40, at opposite sides of the framework 7. These comprise cylinders 41 and elongated piston rods 42 connected to pistons (not shown) which operate within the cylinders.

The lower end of each cylinder is pivotally connected, as at 43, with the top of a transverse beam 45 bridging and secured to the two side beams 11. The piston rod 42 of each cylinder is pivotally connected, as at 46, with the adjacent upright post 27 of the cradle 6.

The pivotal connections 43 and y46 preferably dispose the cylinders with their axes inclined upwardly and forwardly, in the mixing position of the drum, and it is a feature of this invention that the cylinders remain at substantially the same angle during extension of their piston rods throughout the entire range of tilting motion of the mixing drum to its extreme discharging position seen in FIGURE 2.

Also, according to the present invention, the mixing position of the drum 5 is defined by a pair of blocks 48 carried by the framework 7, upon which the bight portion 2S of the cradle seats. Cooperating with the blocks 48 to define the horizontal or mixing position of the drum 5 are other stop means which are provided by brackets 50 extending transversely outwardly fromA the upper ends of the cradle posts to engage stop plates 51 affixed to the front columns 8, as seen best in FIGURES 3 and 5.

The lower link 14 may of itself serve to limit tilting discharge motion of the drum 5, when the link reaches the angular position thereof seen in FIGURE 2. If desired, however, other cooperating stops may be positioned on the cradle and on the supporting framework 7 to limit tilting motion of the mixing drum beyond the position thereof shown in FIGURE 2.

It is also important to note that the links 13 and 14 cooperate with the hydraulic cylinders 40 in such a way that the center of gravity of the mixing drum is always far enough rearwardly to enable the drum to return to its mixing position by gravity. Single-acting cylinders may thus be used to advantage, rather than cylinders of the more costly double-acting type.

From the foregoing description, together with the accompanying drawings, it will be apparent to those skilled in the art that this invention provides simple but improved means for tiltably suspending and controlling the discharging motion of a tilt-type concrete mixer drum, and which means assures controlled pouring of the drum contents from a location considerably forwardly of that which the discharge end of the drum normally occupies during mixing.

What is claimed as my invention is:

l. ln concrete mixing apparatus: a rotatable mixing having a discharge opening in its forward axial end; a vcradle transversely embracing a portion of the drum and in which the drum is constrained to turn on its axis; a supporting framework; and means mounting the cradle on the supporting framework for motion of the cradle and the drum thereon from a defined mixing position of the drum to a discharging position at which the rear of the drum is elevated and the discharge opening in its forward axial end is lowermost, said mounting means comprising a drum suspending structure providing a link having its lower end portion pivotally connected with the cradle to provide for tilting movement of the drum relative to the link about a horizontal axis normal to the drum axis `and intersecting wall portions of the drum intermediate its ends, means pivotally connecting the upper end portion of said link to the supporting framework for backend-forth swinging motion of the lower portion of the link about an axis located above the drum and parallel to said pivot axis at the lower end portion of the link, whereby the cradle and drum are swingably suspended from said link, and guide means on the supporting framework connected with the cnadle and cooperating with said link during movement of the cradle and the drum thereon out of the mixing position of the latter to cause substantial upward motion of the rear portion of the drum rela.-

y tive to its front portion simultaneously with bodily motion of the drum in the forward direction.

2. The concrete mixing apparatus of claim l, wherein the drum has an end wall at its rear with a charging opening therein coaxial with the drum; further characterized by a charging chute on the supporting framework project ing downwardly and forwardly toward the rear of the drum and having its extremity received in said charging opening in the rea-r of the drum; and wherein said guide means and the link constrain the initial movement of the drum and cradle out of mixing position to a. degree of forward bodily motion suicient to assure that `the rear of the d'rum will clear the charging chute before any substantial upward tilting motion of the rear of the drum takes place.

3. In concrete mixing apparatus: a rotatable mixing Adrum having a discharge opening in its forward axial end;

a cradle transversely embracing a-portion of the drum and in which the drum is constrained to turn on its axis; a supporting framework; and means mounting the drum and cradle on the framework for motion thereof in unison from a defined mixing position of the ydrum to a discharging position at which the rear of the drum is elevated and the discharge end of the drum is lowermost, said mounting means comprising an upper supporting structure providing a pendant link pivotally connected at its upper end with the supporting framework for back-and forth swinging movement about a horizontal axis transverse to the drum and above the latter, means pivotally connecting the lower end of the link with the cradle so that the cradle and drum are suspended from the framework by said link, said last named means providing for relative tilting motion between the drum and link about an axis parallel to that at the upper end of the link and passing transversely through a medial portion of the drum, and a lower supporting structure providing a guide link having a forward end pivotally connected with the cradle at a location beneath the drum and having a rear spanish end pivotally connected with the supporting framework at a location behind the drum, the axes of said last two pivotal connections being parallel to those at the ends of said pendant link, and said links cooperating during movement of the cradle and the drum out of the mixing position of the latter to cause substantial upward motion of the rear portion of the ydrum relative to its front portion simultaneously with bodily motion of the drum in the forward direction.

4. The concrete mixing apparatus of claim 3, wherein the drum has an end wall at its rear with a charging opening therein coaxial with the drum; further characterized by a charging chute on the supporting framework projecting downwardly and forwardly toward said wall at the rear of the drum and having its extremity normally disposed in said charging opening; and wherein said links cooperate to effect bodily shifting `of the drum a substantial amount in the forward direction during initial movement of the drum out of its mixing position, to cause the rear of the drum to clear the lower extremity of the charging chute before any substantial upward motion of Vthe rear of the drum takes place.

A5. The concrete mixing apparatus of claim 3, wherein said upper link normally extends downwardly and at a slight forward inclination from its pivotal connection with the supporting framework so that its lower end travels forwardly and upwardly along a path which progressively recedes from a horizontal reference plane during movement of the drum out of its mixing position; and wherein the lower link normally extends forwardly and at a slight downward inclination from its pivotal connection with the supporting framework so that its forward end travels in a path which first approaches and `then recedes from a vertical reference plane during tilting of the drum out of its mixing position.

6. The concrete mixing apparatus of claim 5, wherein the axis of the pivotal connection between the cradle and the lower end of said pendant -link is closely adjacent to the drum axis and passes through a mid-portion of the drum; and further characterized by a pair of substantially upright single-acting hydraulic cylinders reacting between the supporting framework and the cradle at opposite sides of the drum, for moving the drum out of its mixing position, each of said cylinders having an extensible element pivotally connected with the cradle at a point on the latter which is spaced from but substantially directly under said pivotal connection between the cradle and the lower end of the upper link in the mixing position of the drum, and having a non-extensible element pivotally connected with the supporting framework at a point beneath fthe drum and a short distance rearwardly of saidpivotal connection between the cradle and the extensible element, so that said cylinders normally extend upwardly and at a slight forward inclination from their pivotal connections with the supporting framework.

References Cited in the tile of this patent `UNITED STATES PATENTS 

